+/*
+ * page migration
+ */
+
+static void migrate_page_add(struct page *page, struct list_head *pagelist,
+ unsigned long flags)
+{
+ /*
+ * Avoid migrating a page that is shared with others.
+ */
+ if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
+ if (isolate_lru_page(page))
+ list_add(&page->lru, pagelist);
+ }
+}
+
+static int swap_pages(struct list_head *pagelist)
+{
+ LIST_HEAD(moved);
+ LIST_HEAD(failed);
+ int n;
+
+ n = migrate_pages(pagelist, NULL, &moved, &failed);
+ putback_lru_pages(&failed);
+ putback_lru_pages(&moved);
+
+ return n;
+}
+
+/*
+ * For now migrate_pages simply swaps out the pages from nodes that are in
+ * the source set but not in the target set. In the future, we would
+ * want a function that moves pages between the two nodesets in such
+ * a way as to preserve the physical layout as much as possible.
+ *
+ * Returns the number of page that could not be moved.
+ */
+int do_migrate_pages(struct mm_struct *mm,
+ const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags)
+{
+ LIST_HEAD(pagelist);
+ int count = 0;
+ nodemask_t nodes;
+
+ nodes_andnot(nodes, *from_nodes, *to_nodes);
+
+ down_read(&mm->mmap_sem);
+ check_range(mm, mm->mmap->vm_start, TASK_SIZE, &nodes,
+ flags | MPOL_MF_DISCONTIG_OK, &pagelist);
+
+ if (!list_empty(&pagelist)) {
+ count = swap_pages(&pagelist);
+ putback_lru_pages(&pagelist);
+ }
+
+ up_read(&mm->mmap_sem);
+ return count;
+}
+
+long do_mbind(unsigned long start, unsigned long len,
+ unsigned long mode, nodemask_t *nmask, unsigned long flags)
+{
+ struct vm_area_struct *vma;
+ struct mm_struct *mm = current->mm;
+ struct mempolicy *new;
+ unsigned long end;
+ int err;
+ LIST_HEAD(pagelist);
+
+ if ((flags & ~(unsigned long)(MPOL_MF_STRICT |
+ MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
+ || mode > MPOL_MAX)
+ return -EINVAL;
+ if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_RESOURCE))
+ return -EPERM;
+
+ if (start & ~PAGE_MASK)
+ return -EINVAL;
+
+ if (mode == MPOL_DEFAULT)
+ flags &= ~MPOL_MF_STRICT;
+
+ len = (len + PAGE_SIZE - 1) & PAGE_MASK;
+ end = start + len;
+
+ if (end < start)
+ return -EINVAL;
+ if (end == start)
+ return 0;
+
+ if (mpol_check_policy(mode, nmask))
+ return -EINVAL;
+
+ new = mpol_new(mode, nmask);
+ if (IS_ERR(new))
+ return PTR_ERR(new);
+
+ /*
+ * If we are using the default policy then operation
+ * on discontinuous address spaces is okay after all
+ */
+ if (!new)
+ flags |= MPOL_MF_DISCONTIG_OK;
+
+ PDprintk("mbind %lx-%lx mode:%ld nodes:%lx\n",start,start+len,
+ mode,nodes_addr(nodes)[0]);
+
+ down_write(&mm->mmap_sem);
+ vma = check_range(mm, start, end, nmask,
+ flags | MPOL_MF_INVERT, &pagelist);
+
+ err = PTR_ERR(vma);
+ if (!IS_ERR(vma)) {
+ int nr_failed = 0;
+
+ err = mbind_range(vma, start, end, new);
+ if (!list_empty(&pagelist))
+ nr_failed = swap_pages(&pagelist);
+
+ if (!err && nr_failed && (flags & MPOL_MF_STRICT))
+ err = -EIO;
+ }
+ if (!list_empty(&pagelist))
+ putback_lru_pages(&pagelist);
+
+ up_write(&mm->mmap_sem);
+ mpol_free(new);
+ return err;
+}
+